Purchased a brand new vehicle on Saturday, drove it around 60 miles total (so, plenty of time to charge a low battery) and this morning it was dead. I checked with two multimeters because I didn't believe the first one but they both read 3.6v. Road ride is on their way to jump it but I feel this is indicative of a larger issue that a battery could drain that low so quickly.

  • Is it safe to jump a battery this low?
  • Should I be concerned that there is something wrong with this battery and this will continue to happen?
  • What could possibly drain the battery that low, I thought there were things in place to stop such a low discharge?
  • 3
    If it is a new car, are you certain you turned everything off that could drain the battery?
    – Rory Alsop
    Commented Nov 1, 2021 at 13:17
  • 4
    If it is brand new, then take it back under the guarantee.
    – Solar Mike
    Commented Nov 1, 2021 at 13:21
  • Embarrassing , but when I drove home my new 2011 Murano , I pushed the single button- start , stop button. twice ( instead of once to turn off the car) . That turned on accessory mode and the battery was dead the next morning. Charged the battery, took it back to the dealer where they checked everything and found no problem. To the dealers credit the word "fool" never came up in the conversation. Commented Nov 1, 2021 at 19:00

3 Answers 3


Is it safe to jump a battery that low: not really. Make that not at all safe
A healthy battery is about 12.8V
by the time it hits 11V, it is massively discharged already.

To get to 3.6v, you battery is so discharged that you have already damaged it. Or much more
likely, it has already been damaged, causing this voltage.

If you jumpstart it, several things could go wrong:
You could set your battery on fire!! (If the cause is a short in the battery)
You could explode your battery!! (if the cause is a very dry cell)
You could overtax the jump cables. Very likely, actually, with a battery this low and consumer-grade cables.
You could miraculously get your vehicle started. In which case your poor alternator is trying valiantly to not only power your car, but also to charge the battery which will appear very similar to a dead short to it! This can fry your alternator.
You could also fry the brains of either vehicle in the jumpstart, due to the wildly fluctuating voltages experienced during the attempted jumpstart.

To fix:
TAKE OUT your dead battery. Replace with a known working, charged one.
Drive to the nearest battery specialist, have them test the dead battery, and your vehicle's charging system for you.

(or in your case, with a brand new car....)
Phone the dealer, hand them your location along with some choice 4-letter-words, and have them tow their vehicle back at their own expense. And provide you with a loaner until they sort out the problem.

  • 1
    Good answer, but I think I'd leave out the choice 4 letter words for now.
    – Jupiter
    Commented Nov 1, 2021 at 17:30

Glad your issue is resolved. However, I just want to educate you (and anyone else who stumbles on this).

so, plenty of time to charge a low battery

It's a common misconception that an alternator in a car can charge a low battery, but this is incorrect. The old generators would, but an alternator will not charge a drastically low battery. The generators were permanent magnets, but the alternators are electromagnets which allows them to vary the charge. This means if there's not enough voltage, there will be no charging. I've helped people who let their vehicle idle in the driveway for an hour or more with a battery below 8v only to find out their battery was still dead. A good battery charger will do wonders with a low battery and can sometimes bring them back from the brink of death.

Rant over.


I've just had exactly the same issue on a new Mazda CX30. The car was delivered to our home. We sat in it on our drive and took about an hour to set up the sat nav, stereo, and phones when a "low battery" warning came up and "start the engine." The starter wouldn't work, so I put my smart charger onto it. It showed 3.6 volts! I couldn't believe it and went for my multimeter. 3.5 Volts! I left my charger connected, but after 5 minutes it reported that the battery could not be charged. We hadn't even driven it off our drive! Mazda Care is on its way.
UPDATE: The Mazda guy jump started the car, left the engine running for 15 minutes and that put enough in the battery to restart. He thought the battery should be OK. Overnight on a smart charger, showed FULL next morning, charger off for 3 hours the battery showed 12.8v which I understand I'd good. Tested the voltage drop with the starter turning the engine over,10v, again good. After 24 hours, still 12.7v. I'll keep a careful eye on the voltage as the days go on.


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